问题
Assume one client wants to enable camera only and another client wants to enable microphone only.
How to set in Chrome / Firefox?
回答1:
Firefox version >46.0 setting:
Right Click at the page you want > View Page Info > Permission (tab) > Use the Microphone -> Allow.
回答2:
In Firefox, type about:permissions in the location/address bar to access the Permissions Manager, where you can set global as well as per-website permissions for several actions and devices including camera and microphone - See this support article.
I wouldn't know how to do so for Chrome.
来源：https://stackoverflow.com/questions/19545084/allow-sites-to-access-your-camera-and-microphone-in-chrome-firefox-separately